Load-sensing booster for mechanical governors



LOAD-SENSING BOOSTER FOR MECHANICAL GOVERNORS Filed Oct. 21, 1960 July23., 1963 R. F. SUMMERS 2 Sheets-Sheet 1 INVENTOR. 50562 F SummersLOAD-SENSING BOOSTER FOR MECHANICAL GOVERNORS Filed Oct. 21, 1960 July23, 1963 R. F. SUMMERS 2 Sheets-Sheet 2 LOA D INVENTOR. 505a??? J;Summers LOAD 4 77'0 RNEYS United States Patent 3,098,935 LGAD-SENSENGBODSTER FQR MECHANMIAL GUVERNGRS: Robert F. Summers, 22 Putnam Ave,Cambridge 39, Mass. Filed Oct. 21, 1960, Ser. No. 64,225

7 Claims. (6i. 29ll4il) (Granted under Title 35, US. (lode (1952), see.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment of anyroyalty thereon.

This invention rel-ates to speed governors for internal combustionengines and the like and in particular to a load-sensing booster to beused in conjunction with a mechanical governor to improve the speedcontrol of engine-generator sets.

It is well known that wherever an internal combustion engine or the likedrives an electric generator connected to a power line, excessiveoverspeeding may occur when heavy loads are thrown off the generator.This overspeeding is caused by the time lag between the load change andthe closing of the engine throttle by a conventional governor. Theaction of governors is defective in that they cannot act until theengine speed has changed. For each load carried there is a certain speedto which the engine must settle in order that the governor can permitthe supply of suficient power to carry that load. To reduce time lag andto obtain stability of regulation, various types of load-sensingboosters have been devised. Perfect stability of engine regulation wouldinvolve the elimination of inertia of all moving parts in the loadsensing booster and engine throttle assembly, friction in bearings ofsuch moving parts, and lost motion therein.

Inertia of moving parts is detrimental to governor performance, becauseit results in delay in initial movement of the governor linkage whencorrective forces are generated, and because it usually causesovertravel of linkage after corrective forces have ceased. The result isspeed surge which is the undesirable rise and fall of engine speed. Whenthe driven equipment is an alternatingcurrent generator, thecorresponding change in frequency may exceed the tolerable limits. Thishas been a serious problem with military electrical generator sets.

Friction and lost motion in bearings of moving parts are detrimental togovernor performance because they result in a delay in initial movementof the governor linkage when corrective forces are generated, andbecause they introduce a hysteresis loop (dead band) in the motion ofthe governor linkage. The result of the time lag is an undesirable speedsurge, while the result of the hysteresis loop is an inability of theequipment to return to an original speed following a load change andreturn to the original load. Friction in governor linkage pivot bearingshas been found to be the direct cause for the inability of aconsiderable number of engine-generator sets to meet militaryspecifications on speed surge and recovery time after load change, anddead band.

One object of the invention is to provide an improved construction andarrangement for regulating mechanisms of engines whereby the time lag ofthe governor, that is, the period of time passing between a change inload and the positioning of the throttle in accordance with the loadchange, is considerably reduced.

Another object of this invention is to overcome the difficultiesresulting from inertia, friction, and lost motion and provide a governorfor prime movers which is not primarily dependent for its action upon achange of speed in the engine governed by it.

A further object of the present invention is to provide a load-sensingbooster in conjunction with a mechanical 3,hli8,935 Patented July 23,1963 governor on an internal combustion engine, which booster forms avariable, indirect connection between a load supplied by said engine andthe throttle of said engine.

The load-sensing booster constituting the present invention hereinafterdescribed has been developed to fulfill, among others, theabove-mentioned objectives and requirements. Other special objectivesand/or novel features claimed herein will be made apparent from thefollowing description of the herewith illustrated embodiments of theinvention.

In the accompanying drawings forming part of this description:

FIG. =1 is a side elevation of a mechanical governor and theload-sensing booster;

FIG. 2 is an end elevation of the mechanical governor and load-sensingdevice;

FIG. 3 is a side elevation of the mechanical governor and load-sensingbooster looking in the direction of the arrow of FIG. 2;

FIG. 4 is a vertical section of the mechanical governor, parts thereofand the load-sensing booster shown in ele vation;

FlG. 5 is an elevation of an engine-generator set including a mechanicalgovernor and the load-sensing device in relation thereto and showing thewiring diagram of the electric load signal producing means;

FIG. 6 shows the wiring diagram for an alternate method of producing anelectric load signal;

FIG. 7 is a diagrammatic view of two engine-generator sets showing thewiring diagram for connecting two electric load signal means inparallel; and

:FIG. 8 is a fragmentary view of a modified mechanical arrangement ofthe load-sensing booster.

The same numbers of reference refer to like parts in all the drawings.

In order to understand more fully the present invention, the operationof the conventional mechanical governor without the load-sensing boosteris described. Referring to FIG. 2, the governor housing ill contains aset of fly- -weights 12, which generate a centrifugal force when rotatedby the engine 13 (PEG. 5) through the governor mainshaft 14-. This forceis transmitted through a sliding spool 16 and a rocker arm 18 to arocker shaft 26 having a hub 21 rigidly attached to one end. On one endof the rocker shaft Zll a governor output lever 22 is rigidly mounted.Referring to FIG. 5, motion of the governor output lever 22 istransmitted through a throttle rod 24 and throttle lever 26 to an enginethrottle not shown. A gover-nors' spring 28, FIGS. 2. and 3,interconnects an adjustable arm 36 secured to the rocker shaft 20 and aspeed control lever 32. This lever controls the governed speed of theengine 33, and its position can be manually adjusted b y turning a speedcontrol rod 34, FIG. 5.

The load-sensing booster, constituting the present invention, consistsof a tractive type electromagnet having a laminated core 4%, FIG. 4,supported in a mounting bracket 42, FIG. 2, rigidly mounted on thegovernor housing 10* and having a centrally positioned coil 4-4 woundabout it. The coil it has electrical leads coupled to a main generator6% as hereinafter described. A laminated armature 59, corresponding tothe electromagnet 40, is fastened to a plate 52 rigidly attached to thegovernor rocker shaft hub 21. The armature Stl moves with the rockershaft 26 and maintains a small clearance with the electromagnet 4ththroughout its arc of movement. The type of electromagnet and armatureshown is one of several types which could be used. The solenoid type ofelectromagnet having a movable core for an armature is also consideredto be quite suitable. The type of moun ing of the electromagnet can alsobe varied. For example, if the design were changed (FIG. 8) so that thearmature 50 were mounted directly to the output lever 22 rather than therocker shaft hub 21, the same results would be obtained.

The eleotromagnet coil is energized by a small electrical load signalcurrent approximately proportional to the output from the main generator6%. Several methods are known for obtaining the necessary electricalload signal for energizing the load-sensing booster.

A current transformer 62, FIG. 5, may be utilized to obtain theelectrical load signal. The generator 6%, H6. 5, has two power outletconnections, 6 and 66, having a constant voltage maintained by thevoltage regulators commonly included With generators. A power or loadline 68 runs from connection 64, to which the primary of the currenttransformer 62 is connected. The secondary side of the currenttransformer 62 is connected in series with a rheostat 7t) and to coil ofthe booster electromagnet through electrical lead 46 and return throughlead 48. The rheostat 70 is to adjust the load signal strength to thebooster when the installation is first made and periodically thereafterwhen engine conditions change. In the case of direct current generatorsand alternating current generators operating at 100% power factor, thesecondary current is proportional to the electrical load on thegenerator, since the voltage is regulated at a constant value. Anaccurate signal current for operation of the load-sensing booster canthus be obtained. Standard 1tems of electrical equipment are alsoavailable to make corrections in signal current when there areappreciable differences in phase loads. The sensing equipment for eachphase will be similar to that described for a single phase.

An alternate method of obtaining an electrical load signal, applicableto small direct current generator sets may be obtained by using a shunt3%, FIG. 6, instead of the current transformer 62, PEG. 5. The shuntfill, FIG. 6, is placed in series with the power line 68 originating atthe generator outlet connection 64. A voltage drop is developed acrossthe shunt in proportion to the current in the power line 68. This inturn produces a signal current through the load-sensing booster inproportion to the electrical load on the generator.

Engine-generator sets equipped with load-sensing boosters may beconnected in parallel, even though each unit is adjusted forapproximately constant speed governing. Two engine-generator sets, FIG.7, are connected in parallel to common load lines 90 and 92. Thegovernors, not shown, for the engines 13 are equipped with theloadsensing boosters (not shown) previously described, and thegenerators 60 are coupled to the electrical load signal producing meansdescribed above in reference to FIGS. 5 and 6 for the load-sensingboosters. To assure that each generator 60 in parallel carries the samerelative load a tie line consisting of conductors 94 and 96 is used toconnect the respective load signal systems in parallel as shown in FIG.7 wherein conductor 94 connects the rheostats '70 and conductor 96connects the electrical leads 46 of the electromagnetic coils 44 of theload-sensing boosters. This equalizes the load signal voltages atsimilar connections along the tie line. The rheostats 70 are stilleffective in their individual circuits. As a result, the throttleopenings for all engine-generator sets so connected will be the same.This is the requirement for maximum possible output fromengine-generator sets connected in parallel. Engine-generator setsequipped with boosters can be adjusted for paralleling with similargenerator sets not so equipped by breaking the electrical circuits tothe loadsensing boosters. Paralleling can then be carried out in themanner established for engine-generator sets equipped with conventionalmechanical governors.

In utilizing the present invention the engine of the engine-generatorset is set to operate at a fixed governed speed without a load on thegenerator by turning the speed control rod 34 which action is throughthe speed control lever 32 which resists such action, the adjustable arm30, governor spring 28 and through the governor rocker shaft 2 andthrottle connections to obtain the setting of the engine throttle. Aload is thrown on the generator and current flows through the powerline. An electrical signal is picked off by the current transformer 62and supplied the electromagnet 4% of the load-sensing booster. A forceis generated by the electromagnet 40 which acts on the armature 50,which, being rigidly attached to the governor rocker shaft 24), rotatesthe shaft against the action of the governor spring to open thethrottle. The objective is to keep the engine speed constant and to thisend the rheostat '70 can be adjusted to vary the strength of theelectric load signal to the electromagnet. The electric load signalhaving once been adjusted to enable the load-sensing booster to maintainthe fixed rate of speed of the engine at one load, all other loads willbe obtained with no change in speed due to proper variations in theelectric load signal which is directly proportioned to the load on thegenerator, and all throttle positioning required by changes in load isdone by the booster action taken, in the case of decreasing loads, inconjunction with the governor spring.

I claim:

1. In combination with a governor housing, governor rocker shaft, rockerarm, sleeve, flyweights, engine for rotating the flyweights, throttlefor regulating the engine, governor output lever rigidly secured to thegovernor rocker shaft, connection means interconnecting the governoroutput lever and throttle, speed control lever connected to the governorhousing, adjustable arm connected to the governor rocker shaft, governorspring interconnecting the speed control lever and adjustable arm, andmeans for operating the speed control lever of an engine-generator set,a load-sensing booster comprising an armature in rigid mechanicalconnection with the governor rocker shaft, an electromagnet rigidlymounted upon the governor housing in spaced relation to the armature, agenerator connected to said engine, means for producing an electricsignal responsive to the load on the generator, and circuit connectionsfor connecting the generator to the electric signal producing means andthe electric signal producing means to the electromagnet for furnishingpower to the electric signal producing means and the electric signal tothe electromagnet producing a force acting on the armature for makingsubstantially immediate adjustment of the throttle through the governorrocker shaft, governor output lever and throttle connection means.

2. In combination with a governor rocker shaft, rocker arm, sleeve,flyweights, governor housing, engine for rotating the flywe-ights,throttle for regulating the engine, governor output lever rigidlysecured to the governor rocker shaft, connection means interconnectingthe governor output lever and throttle, speed control lever connected tothe governor housing, adjustable arm connected to the governor rockershaft, governor spring interconnecting the speed control lever andadjustable arm, and means for operating the speed control lever of anenginegenerator set, an armature, an armature support means rigidlyconnected to the governor rocker shaft and the armature, anelectromagnet, a support means rigidly connected to the governor housingand electromagnet for supporting the electromagnet in a spaced relationto the armature, a generator connected to said engine, means forproducing an electric signal responsive to the load on the generator,and circuit connections for connecting the generator to the electricsignal producing means and the electric signal producing means to theelectromagnet for transmitting power to the electric signal producingmeans and the electric signal to the electromagnet producing a forceacting on the armature for making substantially immediate adjustment ofthe throttle through the governor rocker shaft, governor output leverand throttle connection means.

3. In combination with a governor rocker shaft, rocker arm, sleeve,fiyweights, governor housing, engine for rotating the flyweights,throttle for regulating the engine, governor output lever rigidlysecured to the governor rocker shaft, connection means interconnectingthe governor output lever and throttle, speed control lever connected tothe governor housing, adjustable arm connected to the governor rockershaft, a governor spring interconnecting the speed control lever andadjustable arm, and means for operating the speed control lever, anarmature, an armature support means rigidly connected to the governoroutput lever and armature, an electromagnet, a support means rigidlyconnected to the governor housing and electromagnct for supporting theelectromagnet in a spaced relation to the armature, a generator, meansfor producing an electric signal responsive and proportionate to thecurrent output of the generator, and circuit connections for connectingthe generator to the electric signal producing means and the electricsignal producing means to the electromagnet for transmitting power tothe electric signal producing means and the electric signal to theelectromagnet producing a force acting on the armature for makingsubstantially immediate adjustment of the throttle.

4. The combination of an engine having a throttle, a governor adapted tooperate said throttle, including a governor output shaft and housing, agenerator connected to the engine, and a compensating mechanismresponsive to voltage change of the said generator, said compensatingmechanism consisting of an armature rigidly secured to the governorrocker shaft and an electromagnet rigidly mounted on the governorhousing in spaced relation to the armature, electrical signal producingmeans for producing an electric signal responsive and proportionate tothe current output of the generator, means electrically connecting theelectrical signal producing rrneans to the generator, and means forsupplying the electrical signal to the electromagnet for substantiallyinstantaneous adjustment of the engine throttle through the governoroutput lever.

5. In combination with a governor housing, governor rocker shaft, rockerarm, sleeve, fiyWei-ghts, engine for rotating the flyweights, throttlefor regulating the engine, governor output lever rigidly secured to thegovernor rocker shaft, connection means interconnecting the governoroutput lever and throttle, speed control lever connected to the governorhousing, adjustable arm connected to the governor rocker shaft, governorspring interconnecting the speed control lever and adjustable arm andmeans for operating the speed control lever, an armature rigidly securedto the governor output lever, an electromagnet rigidly mounted upon thegovernor housing in spaced relation to the armature, a generatorconnected to the engine, means for producing an electric signalresponsive to the load on the generator, and circuit connections forconnecting the generator to the electric signal producing means and theelectric signal producing means to the electromagnet for furnishingpower to the electric signal producing means and the resulting signal tothe electromagnet producing a force acting on the armature for makingsubstantially immediate adjustment of the throttle through the governoroutput lever and throttle connecting means.

6. The engine-generator set of claim 1 in which the electric signalproducing means comprises a transformer having a primary and secondarycoil, the primary coil connected to a load line of the generator, and arheostat connected in series between the secondary coil of thetransformer and the electromagnet.

7. A plurality of engine generator sets of claim 6 in which the electricsignal producing means associated with each one of said plurality ofengine generator sets are connected in parallel by conductor meansconnecting the rheostats and conductor means connecting the returnelectrical leads of the electromagnets.

Blankenbachlor June 11, 1940 Kimball June 9, 1942

4. THE COMIBINATION OF AN ENGINE HAVING A THROTTLE, A GOVERNOR ADAPTEDTO OPERATE SAID THROTTLE, INCLUDING A GOVERNOR OUTPUT SHAFT AND HOUSING,A GENERATOR CONNECTED TO THE ENGINE, AND A COMPENSATING MECHANISMRESPONSIVE TO VOLTAGE CHANGE OF THE SAID GENERATOR, SAID COMPENSATINGMECHANISM CONSISTING OF AN ARMATURE RIGIDLY SECURED TO THE GOVERNORROCKER SHAFT AND AN ELECTROMAGNET RIGIDLY MOUNTED ON THE GOVERNORHOUSING IN SPACED RELATION TO THE ARMATURE, ELECTRICAL SIGNAL PRODUCINGMEANS FOR PRODUCING AN ELECTRIC SIGNAL RESPONSIVE AND PROPORTIONATE TOTHE CURRENT OUTPUT OF THE GENERATOR, MEANS ELECTRICALLY CONNECTING THEELECTRICAL SIGNAL PRODUCING MEANS TO THE GENERATOR, AND MEANS FORSUPPLYING THE ELECTRICAL SIGNAL TO THE ELECTROMAGNET FOR SUBSTANTIALLYINSTANTANEOUS ADJUSTMENT OF THE ENGINE THROTTLE THROUGH THE GOVERNOROUTPUT LEVER.